Foundation structure



Sgpt. 2, 1952 H. P. BURRELL FOUNDATION STRUCTURE 2 SHEETSSHEET 1Original Filed June .13, 1946 I N V EN TOR. f QMZQPEar/efl, My mam Sgpt.2, 1952 Original Filed June 15, 1946 H. P. BURRELL 2,608,830

FOUNDATION STRUCTURE 2 SHEETS-SHEET 2 IN VEN TOR.

% Am" M Patented Sept. 2, 1952 FOUNDATION STRUCTURE Harold P. Burrell,Noroton, Conn., assignor to Western Foundation Corporation, New'York,

N. Y., a corporation of Delaware Original application June 13-, 1946,Serial No. 676,482, now Patent No. 2,593,532 datedApril 22,1952. Dividedand this application October 20, 1948, Serial No. 55,540 I 9. Claims.

This invention relates to foundations for buildings, bridgesand otherstructures. I

An object of the invention is to provide a net and improved type offoundation structure comprising foundation columns angularly disposedrelative to each other, with their upper ends connected together andhaving their lower ends securely engaging the rock formation therebelow,thereby forming a triangular foundation frame in which the base of thetriangle is the rock formation itself. i

Another object of the invention is to provide a foundation of the classknown as a deep' foundation, in which the members composing it aredisposed to form a closed system, in which the. forces acting in themembers are axial, and amenable to exact analysis, and are not subjectto substantial bending.

A further object of the invention is to provide a foundationcomprising-a plurality of caissons at least one of which is inclinedfromthe-vertical, 'and in which the upper ends of the caissons areinterconnected and the lower endsare securely set into sockets formed inthe rock formation therebelow.

A further object of the invention is to provide a foundation structurecomprising drilledin caissons angularly disposed relatively to eachother with their upper ends connected together and having their lowerends set into and bonded to rock sockets in bed rock thereby'forming atriangular foundation frame in which the base of the triangle is bedrock.

Another object of the invention istoprovide a new and improved type offoundation which is simple in construction, andwhich has a high loadbearing strength, the value of which can be computed with exactitude.

Other objects and advantages of my invention will become apparent fromthe following description of a preferred embodimentthereof asillustratedin the accompanying drawings and in which,

Fig. 1 is a diagrammatic representation of a bridge structure supportedon foundations as heretofore used; I

Fig. 2 is a fragmentary representation of a bridge structure assupported on a foundation according to'my invention;

Fig. 3 is an enlarged sectional view of a portion of the structure shownin Fig. 2; and

Figs. 4 and dare enlarged sectional views of modified forms of the lowerend of a foundationmember.

This application is a divisional of my co-pending application, SerialNo. 676,482, filed June 13, 1946, now Patent No. 2,593,532 issuedApril22, 1952, for Foundation Structure and Apparatus for Constructingthe S'ame.-

Certain types of structures, such as bridges, quay walls, crane'runways,dams and so forth, may be subjected to vertical and horizontal forces,the latter resulting, for example, from the braking action 'of a train,earth or water pressure. wind, and similarly acting forces. structuresare frequently located where sound foundation strata lie at greatdepths, while the material above is very soft. -In-such cases, theforces acting on the structure must be carried through thesoft-material'and delivered to the underlying sound strata, such-asbedrock.

In the present state of the art, two" main designs are used, one ofthesebeing large piers 12' shown on the'right hand side of 'Fig. 1, thebase or footing l-ofthe pier -2 resting on bed rock '6 wherever it isaccessible, thepier thussupporting one end 8 ofa bridge structure l0.Due to their relative large size and weight, these large piers areseldom stressed to the safe limit of the material' evenwhen bendingstress is added to the vertical forces'present.

The other of the two main designs presently used is typified by thevertical and batter piles.

illustrated onthe left hand side of Fig. 1. As shown, the verticalforces are carried by relatively slender vertical piers; or -piles l2,while inclined or batterpiles l4 take care of the horizontal forces. Thepiles l2 and M are generally assumed to act as'members of a frame andthus to besubject to axial forces only. As shown, the vertical andinclined piles I2 and I4 are pinned together or otherwise connected attheir upper ends to furnish support for the end l6, of the bridge Ill.The soft earth i8 is excavated to receive the massive pier 2 shown ontheright of the view, but the piles l2 and M are normally driven downthrough the earth I8. until their lower ends 20 and 22 respectively, lieina stratum of relatively firm material 24.

It is thus apparent that the above mentioned assumption that the pilesl2 and I4 act as members of a frame and are subject toaxial forces only,is not correct, because, although the upper ends of the piles l2 and 14are rigidly connected,

their lower ends are not A pile is generally driven into the ground bythe blows of a pile hammer, the point sinking deeper under each blow.Even when the point is driven to firm material, it 'is-not-rigidly fixedin its position because of the yielding nature of the soil which wasThese soft enough to allow the pile to be driven into it. The grounditself not being rigid, cannot provide a rigid connection between thetwo lower move to the right. Thus pile I2 will be subject to bending,and, since it is normallydesigned to support vertical loads only, theincreased stress due to bending must be taken care of by enlarging thediameter of the pile or adding vertical piles. 4 relatively small, butthey do exist and cannot be accurately'determined.

An important feature of my invention is to provide a novel type ofconstruction of a deep foundation to overcome this difficulty, and thisis done by sodisposing the supporting members as to form a closed frame,this is, one in which there can be no lateral movement of the lower endsof the foundation columnsv relative to each other as described above. 4

For this purpose I propose to use two piers or foundation columnsinclined to each other and rigidly connected at their tops while theirlower ends or points reach far enoughinto bedrock or similar firmmaterial-as to form a rigid connection therewith. The third member ofthe frame is thus the bed rock or similar rigid substance. Thefoundation columns, according to my invention, may individually bevertical or inclined to any degree, so long as they are inclined toeachother.- 'As shown in Fig. 2, there. are-two members, 28 and 30,connected together at their upper ends, and extending, downward throughearth or othermaterial34. h A

Their lower ends 3Band=38 respectively, are set into sockets 40 and 42drilledinto the. bedrock 44. As a result, it is obvious that thefoundation framenow.comprisesa triangle having its two legs 28 and 30interconnected at the apex 32, and having their lowerv ends 36 and 38substantially rigidly connected to the bed rock 44 which thus forms thebase .of'the triangle of the frame. Since all the members of thetriangular frame arethus rigidly interconnected, there cannot be anyrelative movement of any of the members,

and a solid foundation is thus formed. It will be understood of course,that fora bridge of any size, it will be necessary to use more thanonefoundation frame.

For purposes of illustration I have shown and described foundationcolumns anchored into rock, of the type known commercially as drilled incaissons. These members would be grouped in pairs, either onever-ticalandone inclined,- or two members inclined in differentpositions or directions. The two membersare connected at their upperends, and have their lower ends anchored into sockets drilled in therock, which thus forms thethird member needed-to close the triangle. I

A drilled-in caisson is made by driving a pipe such as the casing. 46 ofthe batter caisson 30 through the soil indicatedby the layers 34 and 24until it rests on bed rock. The lower end of the pipe is provided with atool steel cutting shoe The movements of the piles may be 41 in the formof a collar attached to the pipe by welding. The soil is removed fromthe inside of the pipe 46 by suitable means, and a socket 42 (seeFigures 2 and 3) of substantially the inside diameter of the pipe 46 isdrilled into the rock 44. The pipe 46 with the cutting shoe 41 thereonis then driven into this socket 42 far enough to form a tight fit withthe upper end of the socket to keep mud, sand and clay from entering thesocket. If the loads are not too high, the socket 42 and pipe 46 arefilled with concrete which completes the caisson 30, except that astructural steel, member 49 as shown in Figure 5, or a steel reenforcingcage 50, as shown in Figure 4, may be placed in the socket 42 andextended 7 into the pipe 46 to provide better anchorage between thecaisson 30 and the rock 44. A full length structural steel unit,preferably an H- beam 52, shown in Figures 2 and 3, may be added in theaxis of the caisson shaft and bonded into the socket 42 at its lower endand to the cap 53 at its upper end, as shown in'Figure 2, to provide agreater load bearing capacity if required. The

column 28 is constructed in like manner as a.

drilled-in caisson with the same kind of anchorage at its lower and itsupper ends in' the rock socket 411 and in the cap 53, respectively.

Where, as in Figures; and 5, the metal reenforcement is extended fromthe socketonly a relatively. short distance into the pipe, the lateralbond provides the load transferring medium,

particularly in the case of tension axially of the column. In the lattercase, that is, when the column constructedas-shown in Figures 4 and 5 issubjected to tension,- the metallic wall of the.

pipe provides the necessarystrength in tension.

Where, as in Figures 2 and 3, the full length.

structural steel unit 52 is employed, it may provide the major part ofthe load carrying capacity in compression or in tension as the designrequires. a I I The horizontal load component of the load .irnposed bythe'bridge frame I!) upon the foundation frame shown in Figure 2 tendsto place the column 30 in compression and thecolumn.28 in tensionaxially of said columns. These forces are transferred to bed rock 44 byvirtue of the rigid anchorage of the lower ends of the columns in-therock sockets 42 and 40, respectively. The vertical load component of theload imposed by the bridge frame I0 tends to place the columns incompreseither up or down and within the'plane of the columns'38 and 28horizontal load components either to the right or to the left in Figure'2 entirely by stresses axially of the said columns.

Although I have described embodimentsof my invention in specific terms,it is to be understood that various changes may be made in size, shape,materials and arrangement without departing from the spirit and scope ofthe invention as claimed. J

Having described my invention, what I-claim and desire to secure byLetters Patent isz' r 1. A foundation structure of skeletal triangularform comprising a cap member comprising. a body of concrete, a pluralityof rock socket'ed nectedtogether onlyat-top and bottom and constitutingthe sole rigid connection between the cap member and bedrock.

22. A foundation extending frombedrock upwardly through overlyingnon-rigid earth strata consistingessentially of a load receiving memberdisposed a substantial distance above bedrock and a plurality of steelreenforced concrete caissons one of which has batterrelative to another,said caissons converging upwardly and"at.their upper ends being coupledtogether by saidjload receiving member, said caissons'diverging;downwardly, and-attheir lower ends being bonded into socketsin said bedrock whereby they ;are iconnected together by saidbedrock,'said'caissons being bound together only at the top and at thebottom, by the load receiving member and by said bedrock respectively asaforesaid, and constituting the principal load transmitting meansbetween the load receiving member and bedrock.

3. A foundation structure comprising a concrete cap member, a pair ofrock socketed cais sons one of which is disposed on a batter relative toanother, each caisson comprising a tubular casing disposed in engagementwith bed rock at its lower end and connected to the cap member at theupper end, a steel core in each casing extending throughout the lengthof the casing and having its upper end bonded into the body of the capand having its lower end extending into a rock socket formed in the bedrock below the end of the casing, and a body of concrete filling thespace between the casing and the core and bonding the lower end of thecore to the side walls of the rock socket, said caissons having rigidconnection with each other only at the top and bottom as aforesaid andcomprising the only rigid load transmitting means between said cap andbed rock.

4. In a foundation, the combination of a load receiving member disposedadjacent the free earth surface at the site and lying at a substantiallydistance above bedrock underlying said site, a plurality of drilled-insteel reenforced concrete caissons having their lower ends bonded insockets in said underlying bed rock and having the upper ends coupled toeach other and to said load receiving member, one of said caissons beingdisposed at a batter relative to another whereby to develop a horizontalreaction in the mass of bedrock between said two caissons upon theexertion of a horizontal force component against said load receivingmember in the plane of said two caissons, said caissons being connectedtogether only at their upper ends and at their lower ends andconstituting the sole rigid connection between said load receivingmember and supporting rock.

5. A foundation extending from bed rock upwardly through interveningstrata comprising a load receiving member disposed a substantialdistance above bed rock and a plurality of caissons at least one ofwhich is inclined to the vertical and has its upper end convergent withrespect tethe upper end of" another of said caissons,-? the bed-rockhaving sockets cut'-therei'nto axially irr line with-said caissons; eachof said "caissons ineluding metallic :reenforcem'ent 'whic'hatfits lowerend-extends into-the corresponding socket and isbonded to the-sidewallsthereof and at its up perend is coupled to "said 1 load receivingnie'r'n'ber wherebyaload in tension maybe sustained-axial ly' ofth ecaissong s aid caissons being connected rigidly only-at their u'p'perandattheir lower ends as aforesaidi'and constituting the pi in'cip'al load"transmitting means between" the 1 load rece ng niember-andbedrock:

16; Fdundation- 'adapted to support aicadjin eluding a substantialhorizontal road component comprisinga load applying v member disposedabove bed rock,=a rooksocketedcaisson extending from said lo'a'd"applying member to bedrock; therebein'g a socket ut into said bed-rockat the lower=end or said caisson, said caisson-co taining a 'steel''corewhich at its upper end is connected to said load applying memberand which at its lower end extends into saidsocket; the w-alls of'the'socket and the included er'id' of the core being'bondedtogetheriby cemenro vide "a connection capable of sustainii'i'g a tension load in saidcore, a, compression sustaining member comprising a column, said caissonand said column being disposed at an angle to each other insubstantially a common vertical plane, the upper end of said core andthe upper end of said column converging into proximity to each other andbeing closely connected to each other and to said load applying member,the lower end of said column bearing upon bed rock to deliver theretothe compression load in the column, said load applying member havingmeans to sustain a load having a substantial horizontal load componentin said common vertical plane.

7. Foundation for anchoring to bed rock a horizontal load componentcomprising a plurality of steel columns having their upper ends disposedat a substantial distance above bed rock and being connected together atsaid upper ends, said columns extending down from said connectionthrough intervening strata to bed rock, at least one of said columnsbeing divergent relative to at least another and being adapted tosustain tension longitudinally thereof, and to deliver said tension loadto bed rock and another of said columns being adapted to sustaincompression longitudinally thereof and to deliver said compression loadto bed rock, there being a socket in the bed rock into which socket thelower end of said one column extends, the side walls of the socket andthe lower end of the said one column being bonded by cement to provide aconnection capable of sustaining the tension load in said one column,and load imposing means connected to the upper convergent ends of saidcolumns for delivering load having a horizontal load component in adirection tending to impose tension upon the said one column andcompression upon said other column.

8. In a foundation adapted to anchor a horizontal load component at onelevel, to bed rock at a substantially lower level, the combination of aload applying member disposed a substantial distance above bed rock, acaisson extending from the member through intervening earth strata tobed rock, said caisson having a steel core, there being a socket in therock, the lower end of the steel core' extending into the socket andbeing bonded thereinto by cement to provide a connection for sustainingtension upon the caisson, a column connected at its upper end to saidload applyingmember and extending down intothe earth to a loadsupporting, stratum to develop support for a downwardly, actingcompression longitudinally of the column, the upper end of the caissonand" the upper end of-';the column converging and said-upper .ends beingconnected together and to said loadapplying member, the lower end ofsaid column being disposed a substantial distance horizontally fromsaid'rock socket by downward divergence of said caisson and said column.l

9. Foundation for anchoring to bed rock a horizontal load component ofastructure to be; supported, comprising a plurality of steel columnsconnected-together at their upper ends, at; least one-of said columnsextending fromsaid connection down through intervening strata to a firmload bearing stratum adapted to support a load incompressionlongitudinally of the column, at least another of saidcolumns extendingfrom said connection divergently relative to said first named columndown through intervening strata to bed rock, and being adapted tosupport a load in tension longitudinally of the column, there being asocket in the bed rock into which socket 8 the lower endof, said lastnamed-column extends, the side walls of the socket and the lowerv end ofsaid last-.named column being bonded by cement to provideaconnectioncapable of sustaining the tension load in ,saidnlast. named column, andload imposing means connectedto the-upper ends of said columns fordelivering load having ahorizontal load component in'a direction tendingto impose compression upon said first named column and tension upon saidlast named column. I

HAROLD P. BURRELL.

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